An Appraisal Of Posterior Circulation Ischemia Via A Combination Of Carotid Contrast-Enhanced Ultrasound And Transcranial Doppler

Objective: To study posterior circulation arterial lesions of patients with posterior circulation ischemia (PCI) via a combination of carotid contrast-enhanced ultrasound (CEUS) and transcranial Doppler (TCD), and to evaluate the clinical significance of carotid CEUS and TCD in early diagnosis and arterial evaluation of PCI.Method: 155 patients with PCI were selected and divided into cerebral infarction group and transient ischemia attack (TIA) group, and 54 healthy subjects were selected as control group. All subjects received carotid CEUS and TCD and some patients underwent cerebral digital subtraction angiography (DSA). Diameter, peak systolic velocity (PSV), the quality and construction of plaque of extracranial vertebral artery, and hemodynamics of intracranial posterior circulation artery of the three groups were compared. Hemodynamics of intracranial posterior circulation artery was compared according to intracranial flow velocity grade. Distribution of PCI arterial lesions was analyzed and the level of atherosclerosis of extracranial internal carotid artery and its effect on hemodynamics of posterior circulation artery were evaluated. The accuracy and reliability of PCI diagnosis via a combination of carotid CEUS and TCD were evaluated by comparison with the outcomes of DSA.Results: The frequency of vulnerable plaque of extracranial vertebral artery atherosclerosis in cerebral infarction group (85%) was significantly higher than that in TIA group (52.7%) (P<0.01). The PSV difference of bilaretal extracranial vertebral artery in cerebral infarction group was significantly higher than that in TIA group and control group (P<0.01) and that in TIA group was much higher than in control group (P<0.05). The pulsatility index (PI) and resistance index (RI) of intracranial vertebral artery and basilar artery in cerebral infarction group and TIA group were much higher than those in control group (P<0.05). The frequency of flow velocity increase and decrease in the two groups were significantly higher than that in control group (P<0.01).The occurrence of intracranial arterial lesions (43.5%) and intra- and extracranial arterial lesions (12.9%) of posterior circulation in cerebral infarction group were significantly higher than that in TIA group (22.6% and 11.8%, respectively). The occurrence of posterior circulation extracranial arterial lesions in TIA group (25.8%) was fairly higher than that in cerebral infarction group(21%). The occurrence of posterior circulation arterial stenosis in cerebral infarction group (27.4%) was significantly higher than that in TIA group (11.8%) (P<0.01). The occurrence of intracranial arterial stenosis in cerebral infarction group (76.5%) was predominant, but that of extracranial arterial stenosis in TIA group (63.6%) was predominant. The occurrence of≥50% stenosis of extracranial internal carotid artery in cerebral infarction group (21%) was significantly higher than that in TIA group (4.3%) (P<0.01). The peak velocity (Vp), PI, RI of intracranial vertebral artery and basilar artery were significantly higher than that in control group (P<0.05) in 11 anterior circulation steal patients.22 patients were given cerebral DSA. Compared with the outomes of DSA, the sensitivity and specificity in detecing posterior circulation arterial stenosis combining carotid CEUS and TCD was 92.9% and 62.5% respectively.Conclusion:①The detecting rate of vulnerable plaque of posterior circulation artery can be raised through carotid CEUS. The occurrence of vulnerable plaque in posterior circulation cerebral infarction is more frequent than that in posterior circulation TIA.②The PSV difference of bilaretal intra- and extracranial vertebral artery is valuable to appraise the severity of posterior circulation arterial lesions of patients with PCI.③The degree of PCI is correlated with the hemodynamic abnormality of intracranial posterior circulation artery, and the frequency of flow velocity decrease is high.④The occurrence of intracranial arterial lesions are more frequent than that of extracranial arterial lesions in posterior circulation cerebral infarction except in case of posterior circulation TIA.⑤It is importanrt to pay attention to anterior circulation arterial lesions of patients with PCI, which helps to identify anterior circulation steal which results from severe internal carotid artery atherosclerostic stenosis or occlusion early.⑥It's accurate and reliable to diagnose PCI combining carotid CEUS and TCD, especially to appraise hemodynamics. It could never be superseded by DSA.